Feature 'read on open for DoM files' breaks GSS integrity check.
Indeed, when ski or krb5i flavors are selected, GSS integrity mechanism signs requests on client side before they are sent, and then checks signature on server side upon receiving.
So it is not possible to alter the request content once signature is calculated.
However, with the patch implementing 'read on open for DoM files' (https://review.whamcloud.com/23011), the value of request->rq_reqmsg->lm_repsize is changed after the request has been wrapped. And this field is included in request->rq_reqbuf on which the signature is calculated.
So the signature calculated on the received request on server side does not match the signature calculated on client side.
Consequence is that it is not possible to use Kerberos or Shared Key with integrity protection flavors (and possible full encryption flavors as well).
Bug
Critical